c********l
发帖数: 8138 | 1 http://www.davidhunt.ie/piphone-a-raspberry-pi-based-smartphone
除了上面介绍的树莓派和Adafruit显示屏之外，PiPhone使用的重要部件还有Sim900
GSM/GPRS模块，用于语音控制这一块。
从上面的视频介绍中可以看到，PiPhone配备了一个SIM卡槽，它可以像普通手机一样进
行语音通话、发送文本信息以及访问数据等。
据悉，PiPhone这款DIY手机的造价为158美元
PiPhone – A Raspberry Pi based Smartphone
BY DAVEH | PUBLISHED APR 25 2014
IMG_0872cHere’s my latest DIY project, a smartphone based on a Raspberry Pi
. It’s called – wait for it – the PiPhone. It makes use an Adafruit
touchscreen interface and a Sim900 GSM/GPRS module to make phone calls. It’
s more of a proof of concept to see what could be done with a relatively
small form factor with off-the-shelf (cheap) components. I don’t expect
everyone to be rushing out to build this one, but I had great fun in doing
it, as it builds quite nicely on my previous projects, especially the Lapse
Pi, a touchscreen time-lapse controller, and uses most of the same hardware.
What makes this different from the Timelapse controller is the addition of a
a SIM900 GSM module, which is connected via UART to the Raspberry Pi. Also,
I got myself a LiPo battery that would fit nicely between the TFT screen
and the Raspberry Pi, so it could be used standalone, without any wires
hanging off it whatsoever. Here’s the finished PiPhone.
IMG_0872d
Also shown in the above pic is the touchscreen interface I developed for the
purpose of this project. It’s a numeric keypad, with a display of the
number to dial at the top, and a phone icon at the bottom to make or hang up
the call.
Here’s a demo of the PiPhone in action.
Once we turn the unit over, we can see the main communications module, which
is a Sim900 GSM/GPRS module. This allow us to send standard AT commands to
it to make calls, hang up, send texts, data etc. Overall a very clever
module. Towards the bottom of the white PCB, you can see the SIM Card, which
allows the module to associate with my local GSM network, and it’s using a
regular prepaid SIM card, bought in my local phone store for 0. Below the
GSM module, you can see the on.off switch and a DC-DC converter, which
converts the 3.7volts from the LiPoly battery to 5volts needed by everything
else. The DC-DC converter is from eBay from a UK seller. It was ore
expensive than I’d like to have paid, but It was the last piece of the
puzzle, and I didn’t want to wait the typical 3 weeks from China.
IMG_0868b
The following image gives a better view of the LiPo battery. It’s from
Adafruit http://www.adafruit.com/products/328, which fits nicely between the TFT and the Pi. The only problem with this setup is heat. It gets a bit warm around the CPU if you leave the unit switched on for several minutes, as there’s very little air circulation. With a small fan circulating the air around it, I was able to leave it on for extended periods during development, and it was cool to the touch.
Also, the 6 pin header on the GSM module sticks out a bit, so I though about
de-soldering the header and soldering the wires directly onto the PCB.
That would prevent the connector sticking out so much, and would sit better
when placed on a flat surface.
IMG_0867b
And the other side view, showing the foam-core board seperating the GSM
module from the Raspberry Pi. I chose a nice thich piece to ensure no
electrical connections between them. Oh, and a couple of well placed cable-
ties was all that was needed to hold everything together. :)
IMG_0869b
And one last pic showing the Adafruit TFT on top.
IMG_0866b
I presented this to my local FAbLab the night before the publication of this
blog article, and one question from the audience stood out: “Do you have
to pay for credit?”. That certainly made me think, and we had a good giggle
at that. Yes, you still have to pay for credit in the usual way, purchase a
SIM card from a local service provider. This is not going to get you free
calls! Nice try though! :)
Costs:
Raspberry Pi Model B – $40
PiTFT Touchscreen 320×240 – $35
2500mAh LiPo battery – $15
SIM900 GSM/GPRS module – $48
DC-DC boost converter 3.3V – 5V 1A – $10
Cables, connectors, switch, etc. - $10
Total: $158
As you can see from the cost of the components, you’d be FAR better off
going into your local phone store and picking up a normal smartphone, but
hey, where’s the fun in that. I got a great kick out of the first phone
call I made with this thing. And it wont’s stay in one piece for long, I’
ll be using those parts for other projects very soon!
Software
If anyone wants the code, let me know, and I’ll upload to GitHub. It’s not
very clean, certainly not as clean as the LapsePi cocde, so if you’re
looking for some PyGame code to do a user interface, you could do worse
than to start with the PiTFT Camera by Phil Burgess, which all this display
stuff is based on.
Circuits
None. :) It’s all made from off the shelf components. | c********l
发帖数: 8138 | 2 Zed
April 25, 2014 at 9:07 pm #
Ever heard of http://www.amazon.com?
http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps
shows LOADS of smartphones < 158$ without a contract… | n****i
发帖数: 1024 | | c********l
发帖数: 8138 | 4 150刀以下的smart phone，有没有办法自定义OS？
【在 n****i 的大作中提到】
: 有158刀，可以买很不错的聪明手机了
| p*******o
发帖数: 6791 | 5 这个不错，搭手机没用，照这思路搭个portable的mame 模拟器，带物理按键的那种。 |
|
